The primary objectives in this proposal are to: (1) correlate alterations in the somatosensory evoked potential (SEP) with specific spinal cord lesions, (2) study the electrophysiological alterations occurring in the SEP following graded trauma, (3) study the effects of trauma and the influence of other agents on the isolated, in vitro spinal cord, (4) develop and test methods of computer analysis for the rapid recognition, differentiation and characterization of SEP's. Methods used entail the following: (1) measurements of amplitude, latency configuration and Euclidean distance, (2) the use of a standard weight drop apparatus to produce trauma, (3) the use of the recorded far-field potential to determine its effectiveness as a reliable measure of spinal cord trauma, (4) use of an in vitro spinal cord model to separate effects of mechanical trauma from ischemia induced necrosis resulting from impaired microcirculation, (5) development of a reliable model to mimic spinal cord trauma, (6) continued development and application of computer analysis techniques for SEP classification.